WorldGuard Regions Not Working

On my server, I made a spawn and worldguarded it. I made it so that players cannot place blocks etc. I made a Chestshop too, and I made a separate worldguard region for it. I downloaded another plugin that allows placing of signs even in worldguard regions, but doesn't allow placing of other blocks. It sorta works, but only in certain parts of the room. I worldguarded the Whole room, but I can only seem to place signs in the middle of it. I cannot place signs near the edge of the region, because it says I don't have permission (I was in the Default Group, to make sure they can play signs everywhere). So as of now, Default group can place signs in the middle of the room, but not the edges. As OP, I can everywhere though. Why is the region only allowing signs being placed in some of the area, but not the full Region? Please Help!

 

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